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Surgical Technique


Cutting the risk of hysteroscopic complications

Proper selection and treatment of patients and prompt intervention minimize complications and legal risks of this effective, underutilized procedure.

January 2004 · Vol. 16, No. 1

KEY POINTS

  • Preoperative treatment with a gonadotropinreleasing hormone agonist increases the odds of operative complications by a factor of 4 to 7.
  • Preoperative cervical ripening reduced the need for cervical dilation, minimized cervical complications, and reduced operative time.
  • CO2 should never be used for operative hysteroscopic procedures because of the high risk of CO2 embolism.
  • Ultrasound guidance may improve outcomes in selected hysteroscopic procedures.

The state of the art can be simply put: Hysteroscopy is underutilized. Most studies consistently demonstrate the safety and efficacy of operative hysteroscopy, as well as high patient satisfaction.

It is a valuable tool in the evaluation and treatment of infertility, recurrent pregnancy loss, and abnormal and postmenopausal uterine bleeding, and is useful when saline infusion sonography findings are equivocal.

Further, if a global ablation device fails, the surgeon can convert to hysteroscopic ablation rather than abandon the procedure altogether. This is not as unusual as it might appear: In US Food and Drug Administration trials, there was a staggering 10% to 22% malfunction of global ablation technology.1

Safe, easily learned

Although gynecologists are beginning to embrace this modality, many physicians avoid it because of inadequate training or exaggerated fears of complications. In reality, hysteroscopy is one of the safest and most easily acquired surgical skills in gynecology. For example, in a prospective evaluation of 13,600 diagnostic and operative hysteroscopic procedures performed at 63 hospitals in the Netherlands—which involved both established surgeons and residents—Jansen et al2 found an astonishingly low complication rate of 0.28%, with no deaths.

Proper selection and treatment of patients and prompt intervention minimize complications as well as legal risks. Surgical misadventures and lawsuits occur with delayed intervention, failure to recognize pathology or risky conditions, and inadequate preventive maneuvers.

Overall, emphasis on safety is vital to success, and thorough awareness of potential complications is just as important.

Three types of complications

Complications fall into 3 categories (TABLE):

  • Procedure-related
  • Media-related
  • Postoperative

PROCEDURE-RELATED COMPLICATIONS

Complication rates

In a retrospective investigation, Propst et al3 determined the rate of complications associated with specific hysteroscopic procedures. Demographic data and medical histories were collected for 925 women who had operative hysteroscopy in 1995 and 1996. The overall complication rate was 2.7%. Myomectomy and resection of uterine septa carried the greatest odds of complications; polypectomy and endometrial ablation had the lowest. Preoperative treatment with a gonadotropinreleasing hormone (GnRH) agonist increased the odds of complications by a factor of 4 to 7. Women under age 50 were more likely to experience complications than those over 50.

In the study by Jansen et al,2 38 complica-tions occurred in the 13,600 procedures. The greatest risk of complications occurred with adhesiolysis (4.48%), followed by endometrial resection (0.81%), myomectomy (0.75%), and polypectomy (0.38%).

Cervical entry requires special attention

Almost half of the complications in the Jansen study were related to cervical entry, so caution and, perhaps, preoperative cervical ripening are advised. Many premenopausal subjects were given GnRH analogues, which may render the cervix more resistant to dilation. Complications associated with a stenotic cervix include a cervical tear, creation of a false cervical passage, and uterine perforation.

Cervical ripening may help prevent uterine perforation. The most common complication, occurring in 14.2 cases per thousand, is uterine perforation.2 The risk of this is highest in postpartum procedures, followed by procedures in postmenopausal, then perimenopausal, women. Patients with endometrial cancer also have a higher rate of perforation.

Risk factors for uterine perforation include:

  • nulliparity
  • menopause
  • use of GnRH agonists
  • prior cone biopsy
  • markedly retroverted uterus
  • undue force

Modern operative hysteroscopes often require dilation of the cervix to a number 8-10 Hegar dilator. Navigation of the internal os is critical before operative instruments can be inserted and the surgical procedure performed. In the past, use of preoperative laminaria was recommended to soften the cervix, except in women with marked cervical stenosis and iodine allergy. Preoperative cervical softening still should be considered in high-risk patients.

Vaginal or oral misoprostol for cervical ripening prior to operative hysteroscopy was evaluated in a randomized trial.4 Researchers found a reduced need for cervical dilation, a minimum of cervical complications, and reduced operative time in study patients compared with controls.

When 400 μg oral misoprostol is given 12 and 24 hours before surgery, it also softens the cervix and eases dilation.5 Although misoprostol has several bothersome side effects (such as lower abdominal pain and slight vaginal bleeding), few if any prevent its use.

Signs of perforation. Patients who sustain uterine perforation with subsequent intraperitoneal bleeding often complain of pain in the abdomen and shoulder, and experience hemodynamic instability. A quick sonographic survey of the abdomen will demonstrate free intraperitoneal fluid. (It is rare for much intraperitoneal fluid to accumulate by transtubal regurgitation during operative hysteroscopy, despite the quantity of fluid used.)

If perforation is suspected, laparoscopy or laparotomy is necessary to clarify the cause of pain, unstable vital signs, or free fluid visualized by ultrasound.6

Exercise extra care and precautions in women who have had a prior cesarean section, myomectomy, or uterine perforation. Complete visualization of uterine landmarks is necessary during operative hysteroscopy to exclude uterine dehiscence, sacculation, and perforation. Prior uterine surgery may cause myometrial weakness and lead to possible perforation. Do not proceed if abnormal uterine morphology is detected. If uterine perforation occurs, injury to bladder and bowel is possible when electrical energy is applied to a uterine wall compromised by prior surgery. Strict visualization of uterine anatomy is critical in this population so that bowel or bladder burns can be avoided.

MEDIA-RELATED COMPLICATIONS

Notorious complications and several recent lawsuits have stemmed from fluid overload. A common element has been the physician’s lack of awareness of how rapidly complications can arise, and what signs and symptoms are specific to the fluid used.

Monitor fluids vigilantly

Operative hysteroscopy must be performed in a fluid medium. The type of fluid depends on the surgeon’s preference and the instrument utilized, but any fluid can be associated with complications. Fluid choices with monopolar instruments include glycine 1.5%, a mixture of sorbitol 3% and mannitol 0.54%, and mannitol 5%. These are frequently used with the continuous-flow resectoscope. Bipolar operative hysteroscopy can be performed using saline.

The solution to media-related complications is basic: vigilant monitoring of fluids. A cavalier attitude, poor fluid documentation, and failure to respond to complications can lead to trouble. If fluid overload occurs, comanagement and consultation with an intensive care specialist is advised.

Distention media

Among the options for distention media in operative and diagnostic hysteroscopy are high-viscosity dextran 70 and low-viscosity fluids such as hypotonic, electrolyte-free and isotonic, electrolyte-containing solutions. The popularity of dextran 70 is waning, however. While it is immiscible with blood, significant complications have been reported.

Signs of anaphylactic reactions to dextran 70 include acute hypotension, hypoxia, pulmonary edema, fluid overload, fulminant coagulopathies, and anemia. The surgeon must operate quickly, minimize endometrial trauma, use continuous pulse oximetry, and obtain a preoperative coagulation panel.

Dextran 70 also can ruin operative hysteroscopes if they are not cleaned promptly and thoroughly after use.

Hypotonic, electrolyte-free solutions. With hypotonic, electrolyte-free solutions such as glycine 1.5%, early recognition of possible complications, including hyponatremic hypervolemia, is vital. For example, when glycine and sorbitol are metabolized, free water accumulates and the body attempts to achieve homeostasis through compensatory mechanisms such as osmosis, which moves free water into extracellular and intracellular spaces. This can lead to increased free water in the brain, resulting in cerebral edema, rising intracranial pressure, and cellular necrosis.

The cerebral cation pump normally pumps osmotically active cations into the extracellular space, thereby minimizing cerebral edema. However, this pump is inhibited by estrogen, so the compensatory mechanism is diminished.

Classic clinical features of hyponatremic hypervolemia include apprehension, confusion, fatigue, headache, mental agitation, nausea, visual disturbances (including blindness), vomiting, and weakness. These complications are more readily apparent when regional anesthesia is used rather than general anesthesia.

If hyponatremic hypervolemia goes unrecognized, bradycardia and hypertension can ensue, followed rapidly by cerebral and pulmonary edema and cardiovascular collapse. In addition, glycine 1.5% is metabolized to glycolic acid and ammonia. Free ammonia is associated with central nervous system disorders. Recognition and prompt treatment by an intensivist may prevent permanent neurologic sequelae, death, and lawsuits.7

Isotonic, electrolyte-containing solutions. Mannitol 5% is electrolyte poor but isotonic, creating less risk for hypo-osmolality. However, dilutional hyponatremia (ie, low sodium levels) can still occur.

Advantages of bipolar instruments. To minimize complications from hypotonic, electrolyte-free solutions, manufacturers developed operative hysteroscopes that can function in a bipolar environment. Bipolar instruments can operate in isotonic, physiologic, electrolyte-containing media. Hyponatremia and hypo-osmolality cannot occur with normal saline or Ringer’s lactate, but fluid overload can. (Fluid overload with saline can cause pulmonary edema and congestive heart failure.)

How much fluid will be absorbed? The answer depends on factors including surface area of the surgical field, duration of surgery, opened venous channels, type of irrigation fluid used, and pressure of the delivery system. Modern gynecologic suites employ fluid irrigation systems that continuously measure input and output, with alarms that signal a predetermined fluid deficit. The alarm indicates the need to halt the procedure and quickly evaluate the patient. Careful attention to the recommendations of Loffer et al8 would lead to fewer complications from fluid mismanagement.

Appropriate use of CO2

High risk of embolism with CO2 in operative procedures. Although diagnostic hysteroscopic procedures often are performed with carbon dioxide (CO2), operative procedures never should be. The reason: the high risk of CO2 embolism that occurs with open venous channels and vascular endometrium. The choice between CO2 and fluid medium for diagnostic hysteroscopy often is determined by physician preference and the presence of uterine bleeding. Many gynecologists prefer CO2 for its optical clarity and patient comfort during insufflation. 9

Purge tubing of room air before each procedure. Embolic complications with CO2 have been recorded with use of the neodymium: yttrium aluminum garnet (Nd:YAG) laser and during operative procedures. Less well known are the adverse sequelae that can occur with room air prior to beginning the procedure. It is critical to purge the entire tubal system with CO2 prior to instrumentation, since up to 40 cm3 of room air may be insufflated into a patient when 200 cm of connective tubing with a 0.5-cm lumen is used. 10 Wait for several minutes before starting the procedure so that the whole system is purged.

Cancer concerns: When is hysterectomy the best option?

One of the greatest concerns about endometrial ablation is that diagnosis of endometrial cancer will be delayed because the endometrial cavity has been obliterated. Vilos19 recently reviewed the salient characteristics and findings in women treated by endometrial ablation who subsequently developed endometrial cancer. A review of the individual cases revealed that most of these patients had numerous risk factors for endometrial cancer.

Review risk factors, chronic conditions

Continued...
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